In the field of high fidelity voice or music reproduction systems, and in particular loudspeakers, substantial and continuous efforts are being made to obtain sound reproduction which is as faithful as possible to the original sounds to be reproduced by the loudspeaker. The problem is most acute for lower frequency sounds, otherwise known as bass sounds, and most loudspeakers fail to faithfully reproduce such bass sounds. Many loudspeakers include at least one speaker driver contained in a cabinet, which may or may not be used to help direct sound waves from the speaker driver. The inherent resonance frequency of the speaker driver and the cabinet function to produce "booming" or unnatural emphasis of base tones of particular frequencies, while de-emphasizing other frequencies, thereby distorting announcements or music broadcast over the loudspeaker.
Sound distortions created by loudspeakers, however, are most particularly acute in large open or enclosed areas such as, for example, stadiums, arenas, airports, train stations, theaters, ice rinks or the like. Most loudspeakers produce sound in only one direction and, therefore, must be aimed towards the audience for all frequencies to be heard. Often, even in areas with good acoustic qualities, dead spots, where sound reproduction is soft or unintelligible, and hot spots, where sound reproduction is uncomfortably high, are created by the loudspeaker. In addition, with most loudspeakers it is often difficult to project sound to persons furthest from the loudspeakers without making it uncomfortably loud for persons nearest the speaker. What would be best is a loudspeaker that provides an omni-directional radiation pattern that decreases or eliminates the creation of dead and hot spots when broadcasting in large open or enclosed areas.
In general, nearly all speaker drivers reproduce sounds with a vibrating diaphragm. As the diaphragm vibrates, sound waves are propagated both in front of and behind the speaker driver. The sound waves on opposite sides of the speaker driver are 180.degree. out of phase and provision must be made to prevent the sound waves from canceling each other out. Normally, this is accomplished by mounting the speaker driver in an appropriate enclosure or cabinet, which is employed to contain or dissipate the "rear" sound wave and permit free radiation of the "front" sound wave. Alternatively, the rear sound wave is useful only if it is in phase or augments the front sound wave. What would be best is a loudspeaker that is adapted to harness the rear sound wave in addition to providing omni-directional radiation.
What is desired, therefore, is a loudspeaker that provides omni-directional radiation, especially with low frequencies, that decreases or eliminates the creation of dead and hot spots when broadcasting in large open or enclosed areas. Preferably, the loudspeaker will utilize the rear sound waves created by its speaker drivers. In addition, the loudspeaker should have a rigid and durable, yet light-weight cabinet, and still be able to be hung from above and support weight hung below.